The President attached a signing statement to McCain's Al Quida Bill of Rights. Signing statements are usually attached to "clarify" what the Executive find the intent of the bill to be.
McCain attached his terrorist rights bill to a defense bill and dared the President to deny funding to the troops. He threatened a 2/3rd's overturn of a VETO, and spineless "Republicans" gave him the backup he needed. Only nine voted against the McCain bill in the Senate.
The President did threaten a VETO because protecting the hides of terrorists in war is absurd, but understanding the Senate didn't have the guts to buck McCain he agreed to sign it. Unbeknowst to McCain, Lindsey and Dems he attached the signing statement implying he would follow the bill, except when it conflicted with his constitutional rights as the Executive and Commander in Chief.
This sets up a challenge to the Supreme Court if McCain/Linds/Dems can find a test case of the president authorizing what they believed they outlawed in this bill. Mccain/Linds/Dems are upset the president found a means around the attempted set up to limit our abilities to fight the WOT. Finding a test case, then taking it up through the Courts, will take a few years. By that time the President will be out of office or nearly gone, and may have changed the court fully in such a way they'll agree with the president's intent. It's a gamble on the president's part, and the RINO's/Dems are stating this is an example of the president "announcing himself King unbeholden to law".
And what did they call what they were doing, other than binding the president's hands?